EP4008623A1 - Fahrradgangschaltung - Google Patents

Fahrradgangschaltung Download PDF

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Publication number
EP4008623A1
EP4008623A1 EP21210997.9A EP21210997A EP4008623A1 EP 4008623 A1 EP4008623 A1 EP 4008623A1 EP 21210997 A EP21210997 A EP 21210997A EP 4008623 A1 EP4008623 A1 EP 4008623A1
Authority
EP
European Patent Office
Prior art keywords
gearshift
shaft
rotation
rotation axis
respect
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21210997.9A
Other languages
English (en)
French (fr)
Inventor
Piero PERUZZO
Cesare Schiavi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Campagnolo SRL
Original Assignee
Campagnolo SRL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Campagnolo SRL filed Critical Campagnolo SRL
Publication of EP4008623A1 publication Critical patent/EP4008623A1/de
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/16—Tensioning or adjusting equipment for chains, belts or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/12—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
    • B62M9/121—Rear derailleurs
    • B62M9/124—Mechanisms for shifting laterally
    • B62M9/1248—Mechanisms for shifting laterally characterised by the use of biasing means, e.g. springs; Arrangements thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M25/00—Actuators for gearing speed-change mechanisms specially adapted for cycles
    • B62M25/08—Actuators for gearing speed-change mechanisms specially adapted for cycles with electrical or fluid transmitting systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/12—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
    • B62M9/121—Rear derailleurs
    • B62M9/124—Mechanisms for shifting laterally
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/12—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
    • B62M9/121—Rear derailleurs
    • B62M9/126—Chain guides; Mounting thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/10—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like
    • B62M9/12—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving different-sized wheels, e.g. rear sprocket chain wheels selectively engaged by the chain, belt, or the like the chain, belt, or the like being laterally shiftable, e.g. using a rear derailleur
    • B62M9/121—Rear derailleurs
    • B62M9/124—Mechanisms for shifting laterally
    • B62M2009/12406—Rear derailleur comprising a rigid pivoting arm

Definitions

  • the present invention relates to a bicycle gearshift, preferably to a gearshift for a racing bicycle.
  • the gearshift to which particular reference is made is the rear one.
  • Such a gearshift moves the chain among the different sprockets of the sprocket assembly associated with the rear wheel of the bicycle.
  • the rear gearshift performs the function of keeping the chain correctly tensioned when it is engaged by any of the different sprockets and during the gearshifting, so as to prevent the chain from dropping.
  • the rear gearshift typically comprises a first body associated with the frame of the bicycle and a second body that supports a rocker arm.
  • the latter comprises an inner plate, an outer plate and a pair of toothed wheels arranged between the inner and outer plates and configured to engage the chain.
  • inner plate and outer plate refer to the plate of the rocker arm that, when the rocker arm is mounted on the bicycle, faces the wheel of the bicycle and the plate of the rocker arm that, in the aforementioned mounting condition, is arranged in a more external position with respect to the wheel of the bicycle, respectively.
  • the second body is connected to the first body through a pair of articulated connection rods so as to form an articulated quadrilateral actuation linkage.
  • a linkage is actuated mechanically by a sheathed cable or electrically by an electric motor.
  • the second body Upon actuating the aforementioned linkage the second body is moved with respect to the first body so as to move the rocker arm at the sprocket selected by the cyclist and engage the chain on such a sprocket.
  • the rocker arm is rotatably connected to the second body at a predetermined rotation axis.
  • the terms “axial” or “axially” are used to indicate a direction coinciding with or parallel to the aforementioned rotation axis
  • the terms “circumferential” or “circumferentially” are used to indicate a direction that rotates about the aforementioned rotation axis
  • the terms “radial” or “radially” are used to indicate a direction passing through and perpendicular to the aforementioned rotation axis.
  • An elastic element typically a torsion spring, pushes the rocker arm into rotation about such a rotation axis in a direction of rotation that will be indicated hereinafter as "chain tensioning direction".
  • chain tensioning direction When observing the outer plate of the rocker arm mounted on the bicycle from the front, the chain tensioning direction corresponds to a direction of rotation in the clockwise direction of the rocker arm about the aforementioned rotation axis.
  • the rocker arm is subject to oscillations about the aforementioned rotation axis. During such oscillations, the rocker arm moves in a direction of rotation opposite to the chain tensioning direction, causing a momentary detensioning of the chain and a consequent risk of chain dropping.
  • a unidirectional damping device between the rocker arm and the second body.
  • Such a damping device is configured so as to apply a friction force to the rocker arm when the rocker arm is moved about the rotation axis in the direction of rotation opposite to the chain tensioning direction and to allow the rocker arm to be free to rotate in the chain tensioning direction.
  • US 9475547 describes, with reference to figure 7 thereof, an embodiment of a bicycle rear gearshift comprising a unidirectional rotation device consisting of a unidirectional roller bearing 246 and a damping device 238 comprising a friction element 250 having an annular shape and operatively arranged between a shaft 240 fixedly connected to the rocker arm and the unidirectional roller bearing 246.
  • the friction element 250 comprises a frusto-conical or wedge-shaped friction surface that interacts with a sleeve 248 fixedly connected to the inner ring of the unidirectional roller bearing 246.
  • An adjustment element 277 acts on the friction element 250, said element 277 being screwed onto the shaft 240 and exerting an axial preload force on the friction element 250.
  • the Applicant has observed that, due to the frusto-conical or wedge-shaped friction surface thereof, the friction element 250 exerts on the sleeve 248 a thrust having both a radial component and an axial component.
  • the Applicant has identified a series of drawbacks in the aforementioned bicycle gearshift.
  • the aforementioned drawbacks if not properly considered, can cause the gearshift not to have an optimal operating efficiency and constancy of performance over time in response to stresses that would tend to move the rocker arm in the direction of rotation opposite to the chain tensioning direction.
  • the problem at the basis of the present invention is that of making a bicycle gearshift that comprises a damping device that ensures a greater efficiency and constancy of performance over time with respect to that described with reference to the prior art.
  • the present invention therefore relates to a bicycle gearshift, comprising:
  • a friction surface extending axially along a direction substantially parallel to the rotation axis of the rocker arm causes a friction force having only a circumferential component to be generated between the damping device and the unidirectional rotation device and the damping device to exert on the unidirectional rotation device a thrust having only a radial component, that is without undesired axial components.
  • the operating efficiency of the gearshift is thus improved since, once a certain radial preload has been applied to the unidirectional rotation device through the damping device, the entire preload force is converted into a radial thrust on the unidirectional rotation device.
  • the damping device comprises at least two friction surfaces.
  • two friction surfaces they are preferably arranged on opposite sides with respect to the rotation axis, i.e. about 180° from one another.
  • the damping device acts on the unidirectional rotation device in a balanced manner about the rotation axis.
  • the aforementioned friction surfaces are defined on respective jaws.
  • each of said at least two friction surfaces extends circumferentially about said rotation axis for an arc of circumference having a center on said rotation axis and a center angle lower than 180°.
  • said center angle is comprised between 80° and 160°, more preferably between 110° and 140°, even more preferably it is equal to about 125°.
  • the damping device comprises at least one thrusting member configured to thrust said at least one friction surface against said unidirectional rotation device with a predetermined load.
  • Such a thrusting member determines a preload force that, in turn, determines the value of the radial thrust exerted by the damping device on the unidirectional rotation device, and thus the extent of the damping action.
  • the thrusting member makes it possible to recover possible dimensional divergences from the design dimensions caused by wearing or dimensional tolerances, contributing to actuate the abovementioned automatic compensation.
  • the provision of the aforementioned thrusting member allows to define the desired thrusting force in the assembly step of the gearshift, making it superfluous and/or needless any post-sale maintenance intervention aimed at adjusting the thrusting force exerted by the damping device on the unidirectional rotation device. Such an intervention would indeed by onerous since it would require the complete dismounting of the rocker arm, of the first elastic element and of the damping device.
  • said at least one thrusting member comprises a second elastic element housed in a through hole formed in said shaft along a direction perpendicular to said rotation axis.
  • said second elastic element is arranged in a radially inner position with respect to the two friction surfaces.
  • the second elastic element crosses the shaft and pushes, at the two end portions thereof, the two opposite friction surfaces against the unidirectional rotation device with the same force. Therefore, the radial thrust that is exerted on a friction surface is counteracted by the opposite friction surface through the second elastic element.
  • the second elastic element is a helical spring.
  • the radial thrust is solely a function of the elastic constant of the helical spring.
  • the assembly step of the gearshift it will be possible to select, among various possibly available springs, the one having an elastic constant suitable for applying the desired radial thrust on the unidirectional rotation device.
  • the two friction surfaces are formed on respective jaws provided with respective seats configured to house a respective end portion of the second elastic element.
  • Such seats contribute to prevent undesired axial movements of the second elastic element, ensuring that the entire preload force applied by the thrusting member is converted into a radial thrust.
  • said at least one thrusting member comprises at least one cup spring or at least one helical spring arranged between said shaft and said at least one friction surface.
  • the radial thrust is only a function of the elastic constant of the spring(s). In this case, however, the radial thrust that is exerted on a friction surface is counteracted by the shaft.
  • the damping device comprises an adjustment device configured to adjust said predetermined load.
  • said adjustment device comprises at least one first spacer element having a predetermined thickness.
  • Such an adjustment device can be arranged between said at least one thrusting member and said at least one friction surface or between said at least one thrusting member and said shaft or both between said at least one thrusting member and said at least one friction surface and between said at least one thrusting member and said shaft.
  • the first spacer element can, for example, be a washer having a calibrated thickness.
  • the assembly step of the gearshift it will be possible to select, among possibly available spacer elements having different thicknesses, the one having a thickness suitable for applying the desired radial thrust on the unidirectional rotation device.
  • said adjustment device comprises a preload device comprising a thrusting pin moveable in a first hole extending in said shaft along a first direction perpendicular to the rotation axis and exerting a thrust on at least one thrust plate moveable in a second hole connected to said first hole and extending in said shaft along a second direction perpendicular to the rotation axis.
  • the second hole is arranged in a radially inner position with respect to said at least one thrusting member.
  • the preload device makes it possible to adjust the preload force applied by the damping device on the unidirectional rotation device as desired.
  • the first hole and the second hole are substantially perpendicular.
  • said thrusting pin comprises a substantially wedge-shaped end portion.
  • said at least one thrust plate comprises a substantially wedge-shaped end portion in abutment with the substantially wedge-shaped end portion of said thrusting pin.
  • the aforementioned wedge-shaped surfaces are inclined by about 45° with respect to the rotation axis, but they can also be inclined by different angles, comprised between 15° and 75°. In this way, the movement of the pin along the axis thereof is converted into a radial movement of the thrust plate, and the choice of the angle of inclination provides a greater or lower adjustment sensitivity.
  • the axis of the pin is substantially perpendicular to the rotation axis.
  • said adjustment device comprises a second spacer element having a predetermined thickness, the second spacer element being housed in a through hole formed in said shaft along a direction perpendicular to said rotation axis and arranged in a radially inner position with respect to said at least two friction surfaces.
  • said at least one thrusting member comprises a plurality of cup springs housed inside a bushing which is housed in said through hole and which is arranged on opposite sides with respect to said second spacer element.
  • the radial thrust that is exerted on a friction surface is counteracted by the opposite friction surface through the second spacer element and the cup springs.
  • the radial thrust exerted by the damping device on the unidirectional rotation device is therefore a function of both the elastic constant of the cup springs and the thickness of the second spacer element. In the assembly step of the gearshift it is thus necessary to suitably select, among various springs and various spacer elements, those having an elastic constant and a thickness, respectively, suitable for applying the desired radial thrust on the unidirectional rotation device.
  • said shaft comprises, in a radially inner position with respect to said damping device, an enlarged portion.
  • said enlarged portion comprises at least one flat surface.
  • said enlarged portion comprises a flat surface facing a respective friction surface.
  • said adjustment device is arranged at said enlarged portion.
  • the through hole configured to house the helical springs and/or the cup springs and/or the second spacer element discussed above is therefore formed on said enlarged portion and opens out onto two opposite flat surfaces of such an enlarged portion.
  • the flat portion defines an abutment surface for the end portion of the thrusting member opposite the one which exerts the thrust on the friction surface.
  • the unidirectional rotation device comprises a radial bearing having an outer ring fixedly associated with said second body and an inner ring operatively associated with said at least one friction surface.
  • the radial bearing is a roller bearing, so as to contain the radial dimensions of the bearing.
  • the damping device is at least partially arranged in a radially inner position with respect to said inner ring.
  • the gearshift in this case, has a small axial dimension.
  • the damping device is entirely arranged in a radially inner position with respect to said inner ring.
  • the damping device is at least partially arranged in a radially inner position with respect to an annular element fixedly associated with, and axially adjacent to, said inner ring.
  • the gearshift comprises a self-lubricating bushing arranged between said shaft and said inner ring.
  • Such a bushing ensures the precise centering of the shaft with respect to the unidirectional rotation device, and thus with respect to the damping device, without generating undesired additional friction (i.e. further friction with respect to the friction force generated by the friction surface) between the damping device and the radial bearing.
  • the annular element has a diameter greater than that of the inner ring of the radial bearing.
  • the annular element is axially arranged between the inner ring of the radial bearing and the rocker arm.
  • the gearshift of the invention comprises a pair of axial abutment surfaces arranged on opposite sides with respect to said damping device and configured to prevent an axial movement of said damping device, in particular of the friction surfaces.
  • a first surface of said axial abutment surfaces is made in a single piece with the shaft.
  • the first axial abutment surface is axially adjacent to the enlarged portion of the shaft, more preferably it is arranged between the enlarged portion of the shaft and the rocker arm.
  • the first axial abutment surface is formed substantially at the middle of the shaft.
  • the other of the aforementioned axial abutment surfaces can be defined by the interface surface between the inner ring of the radial bearing and the aforementioned annular element, when provided, or by a flange associated with an end portion of the shaft opposite the one associated with the rocker arm, when the aforementioned annular element is not provided and the damping device is housed inside the inner ring of the radial bearing.
  • said first elastic element comprises a helical return spring.
  • the damping device can be arranged at least partially in a radially inner position with respect to said return spring. Such a provision makes it possible to keep the axial dimensions of the gearshift low.
  • the damping device is entirely arranged in a radially inner position with respect to said return spring.
  • the damping device can also be arranged at least partially in an axially adjacent position with respect to said return spring. This is the case for example when the damping device is arranged at least partially in a radially inner position with respect to the inner ring of the radial bearing, which is arranged at least partially in an axially adjacent position to the return spring.
  • reference numeral 10 indicates a bicycle gearshift according to a first preferred embodiment of the present invention.
  • a rear gearshift i.e. a gearshift configured to be mounted on a bicycle frame (not shown) to move the chain (not shown) among the different sprockets (not shown) of the sprocket assembly associated with the rear wheel of the bicycle.
  • the movement of the chain is actuated through the movement of a rocker arm 20. Such a movement is a consequence of the movement of an actuation linkage 30.
  • the gearshift 10 can be mechanically actuated (through a sheathed cable) or motorized (through an electric motor).
  • the attached figures show, as a non-limiting example, a motorized gearshift, wherein the movement of the rocker arm 20 takes place by means of a motor member 32 that is suitably driven, typically electrically. Once the motor member 32 is driven, the actuation linkage 30 deforms and the rocker arm 20 moves.
  • the actuation linkage 30 is an articulated quadrilateral linkage, preferably an articulated parallelogram linkage. It comprises a first body 34 configured to be associated with the frame of the bicycle, a second body 36 configured to support the rocker arm 20 and a pair of articulated connection rods 38 that connect the first body 34 and the second body 36.
  • the connection rods 38 are also respectively called “inner connection rod” and “outer connection rod”, with reference to their relative position with respect to the frame of the bicycle.
  • the rocker arm 20 is associated with the second body 36.
  • the motor member 32 is housed in the first body 34 and drives the deformation of the actuation linkage 30, lengthening or shortening a diagonal of the articulated quadrilateral.
  • a lengthening of such a diagonal is used to carry out an upward gearshifting (towards a sprocket having a greater diameter), whereas a shortening of the diagonal is used for a downward gearshifting (towards a sprocket having a smaller diameter).
  • the second body 36 Upon deformation of the actuation linkage 30, the second body 36 is moved with respect to the first body 34, the rocker arm 20 moves to the sprocket selected by the cyclist and the chain is engaged by such a sprocket.
  • the rocker arm 20 comprises a pair of opposite plates 22, an inner one and an outer one, and a pair of toothed wheels 24a, 24b arranged between the inner and outer plates 22 and configured to engage the chain.
  • the outer plate 22 is adjacent to the second body 36.
  • the rocker arm 20 is rotatably connected to the second body 36 at a predetermined rotation axis X substantially perpendicular with respect to the planar extension of the outer plate 22.
  • a shaft 23 is fixedly associated with the outer plate 22 of the rocker arm 20. Such a shaft 23 extends coaxially to the rotation axis X through the second body 36 and is configured to rotate as a unit with the rocker arm 20 with respect to the second body 36 about the rotation axis X.
  • a fixing element 62 is coupled with the outer plate 22 of the rocker arm 20.
  • the fixing element 62 can be co-molded, glued, embedded with interference or joined in other per se conventional ways to the outer plate 22.
  • the fixing element 62 has a hole 63 extending coaxially to the rotation axis X.
  • An end portion 23a of the shaft 23 passes through a through hole 22a formed in the outer plate 22 and is housed in the hole 63 of the fixing element 62, for example through an interference or threaded coupling.
  • An opposite end portion 23b of the shaft 23 passes through a through hole 36a formed in the second body 36 and couples with a ring nut 37a.
  • the through hole 36a is formed in an insert 36c co-molded with the second body 36.
  • a support bearing 37 is arranged between the end portion 23b and a corresponding end portion of the second body 36. Such a support bearing 37 is housed in a seat 36b of the second body 36 coaxial to the rotation axis X. In the non-limiting example shown in figures 1-3 , the seat 36b is formed in an end portion of the insert 36c.
  • the ring nut 37a prevents the support bearing 37 from coming out of the seat 36b and axially locks the shaft 23.
  • the ring nut could be replaced by a Seeger ring.
  • the gearshift 10 also comprises a cover 70 removably associated with the second body 36 through a snap coupling, or a threaded coupling, or an interference coupling, or through screws, gluing or other per se conventional ways.
  • the cover 70 is arranged above the end portion 23b of the shaft 23, thereby also covering the support bearing 37.
  • An elastic element which in the embodiment shown in figures 1-3 is a helical return spring 40, is associated with the second body 36 and with the rocker arm 20 so as to push the rocker arm 20 in rotation about the rotation axis X in a chain tensioning direction.
  • the chain tensioning direction corresponds to a direction of rotation of the rocker arm 20 in the clockwise direction.
  • a helical return spring 40 is housed in a seat 42 formed in the second body 36.
  • An unidirectional rotation device 80 is operatively arranged between the shaft 23 and the second body 36. Such a unidirectional rotation device 80 is configured to allow the rotation of the shaft 23 with respect to the second body 36 only in the chain tensioning direction.
  • the unidirectional rotation device 80 comprises a radial bearing having an outer ring 82 fixedly associated with the second body 36 and an inner ring 84.
  • the outer ring 82 is fixedly associated with the insert 36c.
  • the radial bearing is preferably a roller bearing.
  • a damping device 50 is operatively arranged between the shaft 23 and the unidirectional rotation device 80. Such a damping device 50 is configured to apply a friction force to the rocker arm 20 when the rocker arm 20 is moved about the rotation axis X in a direction of rotation opposite to the chain tensioning direction, i.e. - with reference to figure 1 - in the counter-clockwise direction of rotation.
  • the damping device 50 comprises two friction surfaces 52 that extend axially along a direction substantially parallel to the rotation axis X.
  • the two friction surfaces 52 are arranged on opposite sides with respect to the rotation axis X, i.e. about 180° from one another.
  • Each friction surface 52 is defined on a jaw 54.
  • the jaw 54 has the shape of a cylindrical cap, with a cylindrical surface that defines the friction surface 52 and a flat base surface 53.
  • the jaw 54 in any cross section thereof (i.e. in sections taken according to a plane perpendicular to the rotation axis X), is shaped like a circular segment defined by an arc of circumference and by the cord of this circumference.
  • the friction surface 52 is defined at the aforementioned arc of circumference
  • the flat surface 53 is defined at the aforementioned cord of circumference.
  • the friction surface 52 extends circumferentially about the rotation axis X for an arc of circumference having a center on the rotation axis X and a center angle lower than 180°, preferably comprised between 80° and 160°, more preferably between 110° and 140°, even more preferably equal to about 125°.
  • the friction surface 52 acts directly or indirectly on the inner ring 84 of the radial bearing to obstruct the rotation of the latter.
  • the friction surface 52 is preferably provided with knurlings and/or ribs, to convey the possible lubricant used for the internal members and prevent such lubricant from going on the outermost part of the surface 52, which on the other hand must generate friction.
  • the inner ring 84 of the radial bearing is operatively associated with the friction surface 52 through an annular element 86 fixedly associated with the inner ring 84.
  • the annular element 86 therefore forms part of the unidirectional rotation device 80.
  • the annular element 86 is axially adjacent to the inner ring 84. In particular, it is axially arranged between the inner ring 84 of the radial bearing and the rocker arm 20.
  • the annular element 86 has a diameter greater than that of the inner ring 84.
  • the latter is thus connected to the annular element 86 through a flat annular interface surface 85 that extends perpendicular to the rotation axis X.
  • annular interface surface 85 defines an axial abutment surface for the jaws 54.
  • a washer 88 is arranged between the annular interface surface 85 and the outer ring 82 of the radial bearing, and acts as a spacer.
  • the damping device 50 is arranged in a radially inner position with respect to the annular element 86.
  • the shaft 23 comprises a cylindrical portion 23c adjacent to the end portion 23b and arranged in a radially inner position with respect to the inner ring 84, and an enlarged portion 23d adjacent to the end portion 23a and arranged in a radially inner position with respect to the annular element 86.
  • a self-lubricating bushing 83 is preferably arranged between the cylindrical portion 23c of the shaft 23 and the inner ring 84. Such a self-lubricating bushing 83 supports the shaft 23, ensuring a predetermined radial clearance with respect to the inner ring 84. Such a radial clearance is suitable for avoiding the seizure of the shaft 23, which is subjected to a torsional-flexional load by the rocker arm 20.
  • the self-lubricating bushing 83 performs the same function performed by the support bearing 37. Therefore, there are embodiments in which only the self-lubricating bushing 83 is provided and not also the support bearing 37, embodiments in which only the support bearing 37 is provided and not also the self-lubricating bushing 83, and embodiments (like the one shown in figures 1-3 ) in which both the self-lubricating bushing 83 and the support bearing 37 are provided.
  • the enlarged portion 23d comprises two opposite flat surfaces 23e, each of them facing a respective jaw 54.
  • the damping device 50 comprises a thrusting member 56 arranged between the shaft 23 and a respective jaw 54 and configured to push the jaw 54 against a radially inner cylindrical surface 86a of the annular element 86 with a predetermined load (preload).
  • the thrusting member 56 comprises cup springs or helical springs.
  • a plurality of cup springs 57 is provided at each jaw 54.
  • the damping device 50 also comprises an adjustment device 58 configured to adjust the aforementioned predetermined load.
  • the adjustment device 58 can be omitted.
  • the adjustment device 58 comprises spacer elements 59 having a predetermined thickness, for example washers having a calibrated thickness.
  • spacer elements 59 having a predetermined thickness, for example washers having a calibrated thickness.
  • two washers are provided at each thrusting member 56.
  • Each of the two opposite flat surfaces 23e of the enlarged portion 23d defines an abutment surface for an end portion of the thrusting member 56 opposite the one which exerts the thrust on the jaw 54.
  • the two washers are arranged between the thrusting member 56 and the jaw 54, in particular between the plurality of cup springs 57 and the flat surface 53 of the jaw 54.
  • Such washers can also or only be arranged between the flat surface 23e of the shaft 23 and the end portion of the thrusting member 56 adjacent thereto.
  • a substantially cylindrical seat 53a is formed on the flat surface 53 of each jaw 54, said seat being configured to house the washers and, preferably, at least part of the cup springs 57, so as to prevent undesired axial movements of the latter.
  • An axial abutment surface 51a is made in a single piece with the shaft 23 in a position axially adjacent to the enlarged portion 23d and arranged between the enlarged portion 23d and the rocker arm 20. As shown in figures 2 and 3 , the axial abutment surface 51a is arranged between the enlarged portion 23d and the end portion 23a of the shaft 23 and cooperates with the annular interface surface 85 to hold the jaws 54 in a predetermined axial position.
  • the jaws 54 have two opposite axial abutment surfaces 54a configured to be axially contained by the axial abutment surfaces 51a, 85, with a suitable clearance that prevents the sliding thereof.
  • the damping device 50 as well as the annular element 86, is entirely arranged in a radially inner position with respect to the helical return spring 40.
  • Figures 4 and 5 show a second preferred embodiment of a bicycle gearshift 10 according to the present invention.
  • the bicycle gearshift 10 of figures 4 and 5 differs from the bicycle gearshift 10 of figures 1-3 substantially in that the adjustment device 58 comprises a preload device 158 comprising a thrusting pin 159 and a pair of opposite thrust plates 160.
  • the washers shown in figure 2 are not provided here, but embodiments analogous to that of figures 4 and 5 are foreseen in which washers analogous to those shown in figure 2 are provided.
  • the thrusting pin 159 is moveable inside a hole 23f extending in the shaft 23 at the enlarged portion 23d thereof.
  • the hole 23f extends along a direction perpendicular to the rotation axis X and opens out onto a surface 23g of the enlarged portion 23d that connects the two opposite flat surfaces 23e.
  • Each thrust plate 160 is moveable inside a respective hole 23h which extends in the shaft 23 at the enlarged portion 23d thereof.
  • Each hole 23h extends along a direction perpendicular to the rotation axis X and opens out onto one of the two opposite flat surfaces 23e.
  • Each hole 23h is connected to the hole 23f.
  • the two holes 23h are substantially aligned and can be connected together, to define a single through hole 23h.
  • the thrusting pin 159 when pushed inside the hole 23f and brought into contact with the two thrusting plates 160, causes the movement of the latter in the respective holes 23h.
  • the first hole 23f and each second hole 23h are substantially perpendicular to one another.
  • the thrusting pin 159 and each thrust plate 160 comprise respective substantially wedge-shaped end portions 159a, 160a configured to abut against one another.
  • the aforementioned substantially wedge-shaped surfaces 159a, 160a are inclined by about 45° with respect to the rotation axis X, but they can also be inclined by different angles, comprised between 15° and 75°. The choice of the angle determines the adjustment sensitivity.
  • the thrusting pin 159 is actuated by a dowel 161 screwed into the first hole 23f.
  • the dowel 161 is equipped with a shaped recess 161a configured to couple with a tool (not shown) to be used for the initial adjustment of the gearshift 10.
  • the shaped recess 161a is hexagonal star shaped and is configured to couple with a corresponding tool like for example an Allen key.
  • Each hole 23h, and each thrust plate 160, is arranged in a radially inner position with respect to a respective thrusting member 56, which also in this case comprises a plurality of cup springs 57.
  • each substantially cylindrical seat 53a of the jaws 54 is configured to house at least part of the cup springs 57.
  • FIGS 6 and 7 show a portion of a third preferred embodiment of a bicycle gearshift 10 according to the present invention. What is not shown is identical to what is shown in figures 1-3 .
  • the bicycle gearshift 10 of figures 6 and 7 differs from the bicycle gearshift 10 of figures 1-3 substantially in that the thrusting member 56 comprises an elastic element 256 that is housed in a through hole 223i formed in the shaft 23 along a direction perpendicular to the rotation axis X.
  • the through hole 223i is made at the enlarged portion 23d of the shaft 23 and opens out onto the two opposite flat surfaces 23e.
  • the elastic element 256 is a helical spring.
  • a bushing 224 is arranged between the through hole 223i and the elastic element 256.
  • the bushing 224 contributes to prevent undesired axial movements of the helical spring.
  • the elastic element 256 is arranged in a radially inner position with respect to the two opposite jaws 54.
  • the elastic element 256 thus passes through the shaft 23 and pushes, at the two end portions thereof, the two jaws 54, thus pressing the two opposite friction surfaces 52 against the radially inner surface 86a of the annular element 86 with the same force.
  • Each jaw 54 is provided with a respective substantially cylindrical seat 53a that is configured to house a respective end portion of the elastic element 256.
  • FIGS 8 and 9 show a portion of a fourth preferred embodiment of a bicycle gearshift 10 according to the present invention. What is not shown is identical to what is shown in figures 1-3 .
  • the bicycle gearshift 10 of figures 8 and 9 differs from the bicycle gearshift 10 of figures 1-3 substantially in that the adjustment device 58 comprises a spacer element 358 having a predetermined thickness and housed in a through hole 223i formed in the shaft 23 along a direction perpendicular to the rotation axis X.
  • the through hole 223i is made at the enlarged portion 23d of the shaft 23 and opens out onto the two opposite flat surfaces 23e.
  • the thrusting member 56 comprises a plurality of cup springs 57 arranged on opposite sides with respect to the spacer element 358.
  • the cup springs 57 are at least partially housed in the through hole 223i.
  • a bushing 224 is arranged between the through hole 223i and the spacer element 358.
  • the cup springs 57 are, at least partially, housed inside the bushing 224.
  • the bushing 224 contributes to prevent undesired axial movements of the cup springs 57.
  • the spacer element 358 and the cup springs 57 are arranged in a radially inner position with respect to the two opposite jaws 54.
  • the set of cup springs 57 pushes the two opposite jaws 54, so that the two opposite friction surfaces 52 press against the unidirectional rotation device 80 with the same force.
  • Each jaw 54 is provided with a respective substantially cylindrical seat 53a that is configured to house part of the cup springs 57.
  • the substantially cylindrical seats 53a contribute to prevent undesired axial movements of the cup springs 57.
  • Figure 10 shows a fifth preferred embodiment of a bicycle gearshift 10 according to the present invention.
  • Figure 11 shows a portion of such an embodiment.
  • the bicycle gearshift 10 of figures 10 and 11 differs from the bicycle gearshift 10 of figures 1-3 substantially in that the damping device 50 is arranged in a radially inner position with respect to the inner ring 84 of the radial bearing of the unidirectional rotation device 80. In this case, therefore, the annular element 86 is not provided.
  • the friction surface 52 of the jaws 54 therefore exerts a thrust directly on the inner ring 84 of the radial bearing.
  • the radial bearing is preferably a roller bearing.
  • a fixing element 462 provided with a threaded shank 463 and with a head 464, is fixed to the outer plate 22 of the rocker arm 20.
  • the shank 463 extends coaxially to the rotation axis X and passes through a through hole 22a of the outer plate 22.
  • the head 464 is configured to be housed with axial abutment in a housing seat suitably provided in the outer plate 22.
  • the fixing element 462 can be co-molded, glued, embedded with interference or joined in other per se conventional ways to the outer plate 22.
  • An end portion 23a of the shaft 23 has a threaded blind hole 423a in which the threaded shank 463 of the fixing element 462 is screwed.
  • the shaft 23 can thus rotate as a unit with the rocker arm 20 about the rotation axis X with respect to the second body 36.
  • the shaft 23 comprises an end portion 23a and an enlarged portion 23d.
  • the cylindrical portion 23c shown in the previous figures is not provided.
  • the damping device 50 is arranged at the enlarged portion 23d and is arranged between the enlarged portion 23d itself and the inner ring 84 of the radial bearing.
  • the damping device 50 of the gearshift of figures 10 and 11 comprises two friction surfaces 52 that extend axially along a direction substantially parallel to the rotation axis X and circumferentially about the rotation axis X for an arc of circumference having a center on the rotation axis X and a center angle lower than 180°, preferably comprised between 80° and 160°, more preferably between 110° and 140°, even more preferably equal to about 125°.
  • the two friction surfaces 52 are arranged on opposite sides with respect to the rotation axis X, i.e. about 180° from one another.
  • Each friction surface 52 is defined on a respective jaw 54, identical to the one described earlier.
  • the helical return spring 40 is axially adjacent to the inner ring 84.
  • the helical return spring 40 is axially arranged between the inner ring 84 of the radial bearing and the rocker arm 20.
  • the damping device 50 is therefore in an axially adjacent position with respect to the helical return spring 40.
  • the enlarged portion 23d comprises two opposite flat surfaces 23e, each facing a respective jaw 54.
  • the gearshift 10 of figures 10 and 11 comprises a pair of axial abutment surfaces 451a, 451b arranged on opposite sides with respect to the damping device 50 and configured to prevent an axial movement of the jaws 54.
  • the axial abutment surface 451a is made in a single piece with the shaft 23. In particular, it is arranged between the enlarged portion 23d and the end portion 23a. In the non-limiting example shown in figures 10 and 11 , the axial abutment surface 451a is formed substantially at the middle of the shaft 23.
  • the axial abutment surface 451b is defined by a flange 452 associated with a face of the enlarged portion 23d of the shaft 23 opposite the one facing towards the end portion 23a.
  • the flange 452 is fixed to the shaft 23 through a screw 451c.
  • the jaws 54 have two opposite axial abutment surfaces 54a which are axially contained between the axial abutment surfaces 451a, 451b with a suitable clearance that prevents the sliding thereof.
  • Figure 12 shows a sixth preferred embodiment of a bicycle gearshift 10 according to the present invention.
  • Figure 13 shows a portion of such an embodiment.
  • the bicycle gearshift 10 of figures 12 and 13 differs from the bicycle gearshift 10 of figures 10 and 11 substantially in that the adjustment device 58 comprises a preload device 158 comprising a thrusting pin 159 and a pair of opposite thrusting plates 160.
  • the preload device 158 is totally analogous to the one described above with reference to the second embodiment of the gearshift 10 shown in figures 4 and 5 .
  • damping device 50 shown in figures 10 and 11 could be replaced by the damping device 50 shown in figures 6 and 7 or by the damping device 50 shown in figures 8 and 9 .
  • those skilled in the art can combine the features of the different embodiments of the invention herein described and shown as desired.
  • the radial bearing shown in figures 10-13 is axially adjacent to the helical return spring 40, there are embodiments in which the radial bearing is radially inner with respect to the helical return spring 40, providing a damping device 50 having a low radial bulk or a helical return spring 40 having an increased diameter, thereby obtaining a greater axial compactness of the gearshift 10.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Vibration Dampers (AREA)
  • Mechanical Operated Clutches (AREA)
  • Steering Devices For Bicycles And Motorcycles (AREA)
  • Vehicle Body Suspensions (AREA)
  • Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
EP21210997.9A 2020-12-03 2021-11-29 Fahrradgangschaltung Pending EP4008623A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102020000029612A IT202000029612A1 (it) 2020-12-03 2020-12-03 Cambio di bicicletta

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EP4008623A1 true EP4008623A1 (de) 2022-06-08

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US (1) US11760438B2 (de)
EP (1) EP4008623A1 (de)
CN (1) CN114590355A (de)
IT (1) IT202000029612A1 (de)
TW (1) TW202225031A (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11834131B1 (en) * 2022-06-14 2023-12-05 Ad-Ii Engineering Inc. Rear derailleur
US11814138B1 (en) * 2022-06-28 2023-11-14 Ad-Ii Engineering Inc. Rear derailleur

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120083372A1 (en) * 2010-09-30 2012-04-05 Shimano, Inc. Bicycle derailleur with rotation resistance
DE202014106072U1 (de) * 2014-12-16 2015-01-09 Shimano Inc. Fahrradumwerfer
US9290235B2 (en) * 2013-06-18 2016-03-22 Shimano Inc. Bicycle derailleur
US9475547B2 (en) 2012-02-06 2016-10-25 Brian Jordan Derailleur with damping assembly
US20200369343A1 (en) * 2019-05-24 2020-11-26 Tektro Technology Corporation Bicycle rear derailleur

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014225036A1 (de) * 2013-12-23 2015-06-25 Sram Deutschland Gmbh Fahrradderailleur mit Reibungsdämpfung
US9751590B2 (en) * 2014-08-15 2017-09-05 Sram, Llc Bicycle rear derailleur with a damper assembly
TWI573730B (zh) * 2015-10-23 2017-03-11 Lee Chi Enterprises Co Ltd Bicycle rear derailleur with stable chain function
US10577053B2 (en) * 2017-06-06 2020-03-03 Sram, Llc Damper for a bicycle component

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120083372A1 (en) * 2010-09-30 2012-04-05 Shimano, Inc. Bicycle derailleur with rotation resistance
US9475547B2 (en) 2012-02-06 2016-10-25 Brian Jordan Derailleur with damping assembly
US9290235B2 (en) * 2013-06-18 2016-03-22 Shimano Inc. Bicycle derailleur
DE202014106072U1 (de) * 2014-12-16 2015-01-09 Shimano Inc. Fahrradumwerfer
US20200369343A1 (en) * 2019-05-24 2020-11-26 Tektro Technology Corporation Bicycle rear derailleur

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US20220177076A1 (en) 2022-06-09
TW202225031A (zh) 2022-07-01
CN114590355A (zh) 2022-06-07
US11760438B2 (en) 2023-09-19
IT202000029612A1 (it) 2022-06-03

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